Determination of pregnancy is not certain until the second trimester, at around twenty weeks, when the fetal heart beat can be heard via a fetoscope. Albeit there are presumptive and probable signs associated with pregnancy, like the early morning sickness or the growing size of the abdominal area, these could also be caused by a different pathology. Hence, it can be inevitable for a woman who is not aware of her pregnant state to be exposed to radiation, most especially if she is not aware of her current menstruation cycle.
Radiation exposure usually occurs whenever a person is exposed to cosmic rays, external radiation from radioactive ores, internal exposure through radiation therapy given for treatment in cancer patients, and most commonly through diagnostic x-rays. More often than not, pregnant women who are not aware of their pregnant state could have gotten their diagnostic x-rays taken, which is equivalent to receiving 70 millirem. Also, she could have been exposed to other radiation sources, like watching the television and living next door to a power plant.
But exposure to radiation can have an acceptable limit of 350 millirems for the pregnant woman. For the pregnant woman, the most critical period wherein the fetus will suffer the most health consequences is when the she is exposed to radiation around two weeks to fifteen weeks gestational age. At two weeks gestational age, if the mother is exposed to a radiation that measures greater than 5 rad or 5000 millirem, a miscarriage can take place or even death inside the womb. If the fetus is exposed to radiation at the gestational age of eight to fifteen weeks, the fetus is to suffer a severe brain damage from the exposure.
This can result in lowered intelligent quotients or IQs, mental retardation, stunted growth and other birth defects. Mental retardation is defined as a general developmental disorder characterized by a lower than average intelligence marker and the child is to suffer from limited daily living skills due to limited learning capabilities. Stunted growth in a child will be evidenced by a sluggish growth and development progress, as evidenced by a lower than normal height, weight and even cognitive skills.
After this critical period, the two to fifteen weeks of gestational age, the fetus will unlikely suffer from radiation exposure, unless the exposure is extremely large. Only having been exposed to at least five thousand x-rays at one time can give harm to a 16 week old fetus. At 26 weeks gestational age, the fetus cannot be harmed by radiation exposure, and if ever exposed to radiation, the fetus will unlikely suffer serious health consequences. This can be compared to a newborn being exposed to radiation; the chances of having defects are greatly decreased if not invisible already.
However, some of the effects of being exposed to radiation cannot readily be seen or manifest in the early life. Studies also show that fetuses are extremely sensitive to the cancer causing effects of radiation exposure; hence this can increase their risks in acquiring cancer later in life. Radiation exposure can be limited, if not avoided. The pregnant woman needs to be aware of her physiological state. She would have to consult all of her diagnostic exams and her workplace to her physician, so that radiation exposure can be prevented early on the pregnancy.